1. Field of the Invention
This invention related to mechanical interlocks between a pair of circuit breakers for preventing one of the circuit breakers from closing when the other breaker is closed.
2. Description of the Prior Art
The operation in control of electrical systems, including such devices as reversible motors and multi-speed motors, usually includes a circuit breaker for each motor function. A typical circuit includes, for example, a separate manual button for each breaker for the forward and reverse directions of a motor and for each speed of a multi-speed motor. As a result, actuation of one forward or reverse circuit includes an associated circuit for deactivating the other of the forward and reverse circuits. Notwithstanding such precautions, however, it sometimes occurs due to inadvertence or other reasons that both circuits (forward and reverse control buttons), are actuated simultaneously and thereby cause incorrect phase-to-phase line connections. Another typical circuit involves transfer circuits with normal and emergency sources for which one circuit breaker must be prevented from closing when the other breaker is closed. Thus, there is a need for an interlock between the circuit breakers.
Various interlock devices have been provided for overcoming the problem of simultaneous actuation of circuit interrupters. However, most of such interlocks have not been completely satisfactory for various reasons.